Since the conflict began in 2003, Khartoum has blown hot and cold on the subject of international involvement in the region, as this Backgrounder explains. For years, Sudan denied the conflict completely, even after the United States declared what was going on in Darfur to be "genocide" (CNN). Mounting evidence and growing international pressure ultimately forced Khartoum to admit to mobilizing "self-defense militias," as this BBC Q&A explains, and to allow in the 7,000-strong African Union peacekeeping force. But the government still denies supporting the Arab militias—known as janjaweed—behind most of the civilian murders and displacement, despite clear evidence of its involvement in this 2005 UN investigation (PDF) and many others.

The United Nations has also documented some 1.65 million people made homeless internally, with another 200,000 fleeing to neighboring Chad. The situation in Chad has deteriorated into a crisis that nearly disrupted recent elections. The UN's top official for internally displaced persons this week warned that refugees and aid workers in Chad are threatened by militias (ReliefWeb) (PDF).

The pace of UN action—inaction, say critics—frustrates many, including the American officials who were early proponents of sanctions or some other form of intervention. Human Rights Watch charges the world's great powers with a moral failure in Darfur. But with U.S. forces tied up in Iraq and Afghanistan, Washington is unwilling to lead a Sudan initiative. CFR Fellow Max Boot suggests that, given Europe's reticence on military intervention and the African Union's inability to stop the bloodshed, even mercenaries would be an improvement on the present situation.

So far, Security Council threats of action have failed to impress either Sudan or advocates of a tougher line against Khartoum. The Security Council warned Khartoum to disarm militias or face "further action". That was in 2004. It took until April of this year to get any sanctions passed, and those only apply to four Sudanese officials (PDF).

Now, however, the United Nations has opened another front against Sudan via the International Criminal Court, which has been gathering evidence of genocide and mass rape. The ICC presented a report on the topic to the Security Council last week (Guardian).